1. Field of the Invention
The present invention relates to a configurable electronic circuit board, an adapter for the same, and a designing method of an electronic circuit using the board, and more specifically to a configurable electronic circuit board being capable of realization of an arbitrary actual circuit with ease and being preferable for use in verification and testing of a designed system with use of an actual circuit upon designing a VLSI (very large scale integrated circuit) system composed of one or a plurality of chips of VLSIs, and related to an adapter for the configurable electronic circuit board and to a designing method of an electronic circuit using the configurable electronic circuit board.
2. Description of the Prior Art
Generally, in a design of VLSI system verification and testing thereof are time-consuming. Because much time is required for computation of various simulations by a computer and of fault simulation, the fault being produced as a result of modeling of an actual circuit.
To solve the problems, it has been proposed to perform the verification and testing of such a system using an actual circuit.
For such an actual circuit, a bread board comprising a one-board computer for example is known which is constructed, as illustrated in FIG. 27 for example, by disposing on a system board 16 a chip of a central processing unit (CPU) 10 and a peripheral circuit composed of varieties of general-purpose integrated circuits (IC) 12 such as TTLs, RAMs, ROMs and the like and of programmable logic devices (PLD) 14 for use in decoding of any address and the like, in combination for each system design, and by wiring by soldering with use of printed wiring and jumper wiring.
The design of such an exclusive bread board constructed for each system, which requires a large scale of integration and many logic circuits incorporated therein, takes plenty of time and costs a great deal to form a bread board equivalent to the system as well as suffers from a difficulty, once the system is altered, of correcting it correspondingly.
To solve such problems, an electronic device is disclosed in Japanese Laid-Open Patent Publication No. 63-49831 wherein internal wirings are freely altered at need to realize varieties of logic functions by incorporating a memory device for defining a connection relation among a plurality of logic devices and making rewritable the contents of the memory devices externally.
Additionally, another electronic device is disclosed in Japanese Laid-Open Patent Publication No. 63-50999 wherein internal wirings are freely altered at need to realize varieties of logic functions by providing fuses for defining a connection relation among a plurality of logic devices and fusing the fuse externally.
In the electronic devices described above, sockets are provided for disposing logic devices such as programmable read only memories (PROMs) and MSIs, etc., and wirings are laid for connecting those sockets lengthwise and crosswise, and further wiring exchange devices are disposed at intersections between those wirings, thus assuring arbitrary exchange of the wirings.
The wiring exchange device itself, however, does not include any socket so that it is impossible to omit such a wiring exchange device or mount electronic parts at a position where the wiring exchange device is located and further it is impossible to operate an associated circuit so far as electronic parts are not attached to all sockets.
Additionally, for constructing an one-board computer using PLDs as illustrated in FIG. 28, for example, there may be an occasion in which various sizes of PLDs are mounted on the same board and wired for effective use. For example, a small-scale PLD (S PLD) 14A is required if it corresponds to a small-scale general-purpose IC, or a large-scale PLD (L PLD) 14B is necessary if it corresponds to a large-sized general-purpose IC or an integration of small-scale PLDs 14A. However, in the prior art, electronic circuit parts of different sizes such as a CPU or a large-scale PLD or the like, which are not adapted to fit in typical sockets, fail to be mounted on the electronic device.
Additionally, electronic circuit parts and wiring exchange devices are fixed positionally, making it difficult to alter mutual positions. It is therefore impossible in the prior art to realize an arbitrary circuit.
Moreover, a testing method of an electric circuit composed of electronic devices including a logic integrated circuit removably attached to a socket is disclosed in Japanese Laid-Open Patent Publication No. 56-26269 wherein a dummy circuit instead of the logic integrated circuit is attached to a socket for testing characteristics of the circuit.
In the testing method, however, only a peripheral circuit except for the logic integrated circuit can be tested, but the whole circuit including the logic integrated circuit can not be tested.
Furthermore, in the aforementioned bread board, when wiring and connection are performed with use of a transfer gate liable to be altered in configuration, a system clock can not be raised owing to the delayed operation of the transfer gate resulting in greater delay compared with a complete system.
To solve such difficulty, there is disclosed a method of cooling a system in Japanese Laid-Open Patent Publication No. 63-234174 which requires a cooling device and hence is large-sized.